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Numerous radials back in the day had a centrifugal blower in the nose case right behind the reduction gear.My first thought is I would not place the superchargers in the nose case. The standard location behind the engine seems more durable and easier to plumb.
I didn't know that. A two stroke with an open crankcase, i.e. not using crankcase compression, is significantly more dependent on boost than a 4 stroke, especially this one with it's diminished compression ratio. This would need a multistage turbo.Numerous radials back in the day had a centrifugal blower in the nose case right behind the reduction gear.
That's the beauty of the GM 2-stroke diesel concept. The crankcase has no connection to the mixture path as in a 2-stroke gas job. It's a regular oil bath crankcase with oil pump and galleries like a 4-stroke. Intake and exhaust are side ports, and their relative spacing, plus the boost from the blower accomplishes scavenging and intake simultaneously near the bottom of the downstroke. The only thing at the top of the cylinder is the injector. The ones we had were governed at 2150 RPM (2150 power strokes vs 1075 for a 4-stroke), but I'm sure with a little tweaking they could be run faster.I didn't know that. A two stroke with an open crankcase, i.e. not using crankcase compression, is significantly more dependent on boost than a 4 stroke, especially this one with it's diminished compression ratio. This would need a multistage turbo.
That's the beauty of the GM 2-stroke diesel concept.
Back when I was a kid, the market was flooded with cheap 4 cylinder 2-stroke air cooled engines intended for WWII single-flight target drones. Some of the more poverty stricken EAA homebuilders tried to use them in their experimental aircraft, with disastrous results.I dont think the petrol
2-Stroke is at all suited to the duty cycle of an aero engine.
Good post.Ah, things are not quite as simple as they appear.
granted they were not supercharged but did you know the First Porsche engine to exceed 1 hp per pound was the 4.5 liter 917 flat 12 engine of 1969? forged titanium connecting rods and other parts/materials not used in WW II. People keep wanting to compare modern engines and keep forgetting that the high performance aircraft engines of the day, on hp per pound basis took several decades for even race car engines to beat. And the race car engines were nowhere near as a reliable or durable as the aircraft engines. Your genesis theory needs a bit of work. The electronics in the proximity fuse consisted of a few vacuum tubes that were miniaturized. Want to try to build even a simple computer from a 1980s-90s car using vacuum tubes? reliability of said vacuum tube computer would be measured in minutes if not seconds simply due to the number of parts. BTW at the start of the proximity fuse program they would have been satisfied with a 20-25% dud rate if I remember correctly.
I would also note comparing lead content is a lousy way of comparing fuels. For example the post war Mil-F-5572 fuel specification allowed for 4.6cc of lead per US gallon for not only 115/145 but for 100/130 and even 91/96 fuel. You had to use better base stocks and other components for the higher grade fuel, not just more lead. The civilian ASTM D910-48T specification only allowed 4.6cc per gallon for commercial 115/145, both 100/130 and 108/135 were only allowed 3 CCs per gallon and civil 91/98 octane (yes, 2 points higher) was only allowed 2 CCs of lead.
Wright had to develop a brand new way of putting fins on cylinders for the above 1200hp R-1820s, also used on the 1900hp R-2600s and the R-3350s. They machined grooves into the cylinders that were larger at the bottom than at the top(surface) and formed sheet metal into a W configuration, very long outside arms and very short inside arms. This was "rolled" into the grooves so that the bottom of the W was swaged into the groove for mechanical interlock.
In a lot of cases you not only need the design of the new parts, you need the designs for the machines to make the new parts and in some cases you need the designs for machines that can make the machines that can make the parts you want.
Yes, 2-Stroke diesels for aero use a pretty good, as the lower gas temperatures (due to diesel) mean the piston temperature changes are lower, and eases
cylinder lubrication, so they dont have the same constant tendancy to sieze which petrol-2 strokes do, I dont think the petrol
2-Stroke is at all suited to the duty cycle of an aero engine.
Whether an engine can manage an aircraft duty cycle is all down to design; certainly Fairbanks-Morse, MAN, and others build and built 2-stroke spark-ignition engines for continuous, heavy duty operation. The real problem is that an aircraft 2-stroke would have terrible sfc until direct fuel injection could be made to work.
Please list the 2-stroke petrol engines that you are referring to above.
You cannot compare marine/locomotive or static applications to aero, as the weight requirements are so different its impossible to event compare them (wall thicknesses etc).
As far as improvements ? I would not use any cast aluminum or magnesium
fuel would be diesel or kerosene
I'd increase the power density with something similar to this
Turbo charging was used in WW2 so nothing new there, also I would use turbo compounding as well.
No, you can't, but nor can you compare low-cost, light-duty engines to those designed for aviation use. There's nothing intrinsic to the two-stroke Otto cycle making it unsuitable for aviation use. One maker of two-stroke, spark-ignition engines was McCullough http://enginehistory.org/Piston/HOAE/McCulloch.html For others, see http://enginehistory.org/Piston/HOAE/SChron2S.html. Note this source is limited to horizontally-opposed engines, which are limited to low powers. Rolls-Royce, with the Crecy, was pretty sure it could be done: Rolls-Royce Crecy | Project Gutenberg Self-Publishing - eBooks | Read eBooks online
You only need to know that it works, and how to make it in quantity.Somethings, like the torpedo stuff, are easy to fix.
Other things are not so easy. Just because you know what Xylidine is you have to know what it actually does (how it works, not just that it does it) and you have to know how to make it in quantity.
I didn't want to write a book.Same with the VT fuse, theory was easy, manufacturing the things was a major industrial effort.
So what's needed is to apply a few years of engineering smarts. The real problem with the Gatling cannon is nobody realized how much it could affect air combat. 6-8-12-16 machine guns were the stream of thought, not two that put out the fire of 6. The idea was overlooked, therefore, how to implement the idea in a smaller volume and mass wasn't addressed.Gatling cannon weren't exactly unknown, somebody had put an electric motor, a couple of pulleys and v-belt on a gatling gun back in the 1890s, rate of fire was astounding, so was the weight, feeding it for more than few seconds was a problem. Sticking any sort of gatling gun in a wing was a problem due to the size.
The rocket fuel for RPGs is good old smokeless powder followed by good old ammonium (or Potassium) perchorlate. 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane co-crystal with cyclo tetramethylene tetranitramine isn't needed. We had the rocket propellant then. Bazooka, Panzerschreck and Panzerfaust come together with (then-known) shaped charge warhead.RPGs depend on propellent technology that didn't exist at the time.
We had rockets. We had them on ships. We had them on planes. We had them on men's shoulders.Idea is easy, getting the rocket to ignite reliably and on time is a bit of a problem. Rocket backblast onboard ship might be a bit of a problem.
When I worked at GE Armament Division in '69-'70, they had been addressing the "volume and mass" issue since just after WWII, and the Vulcan, Mini, and Micro were the best the technology could produce over 20+ years of development.The idea was overlooked, therefore, how to implement the idea in a smaller volume and mass wasn't addressed.
No, the .50 Gatling was looked at in late '40s, but then the push was "bigger and better" and the interest was .60 cal and 20MM. Turret mounted Vulcans would have been impractical in WWII bombers, as they take up so much space and weight. The M113 APC-mounted VADS (Vulcan Air Defense System) fills the interior of an armored personnel carrier with ammo drum and feed mechanism. And has less than half a minute of firing time. The only airborne turret mounted Vulcan was the three barrel, slow turning version installed in some Hueycobras and Apaches, and that took up a lot of space, could only carry a few seconds worth of ammo, and was hard to keep on target due to recoil effect when fired off axis. Not the sort of thing to defend you to Berlin and back."So, no, rotary cannons in WWII fighters were not a practical proposition, except MAYBE in a Lightning, Mosquito, Black Widow, or Beafighter. (Let's not forget the skip bombing Mitchells!)"
Mitchell B25, Douglas A26, Martin B-26, de Havilland Mosquito/Hornet , P-38, Any bomber with a tail turret, and that's just a few needing the 20mm
The .50 gatling would strengthen the defensive fire of any bomber with twin .50s mounted anywhere.
Put 2 of each in an F7F, add 2 .50 Gatlings to the 20mm Gatling in strafing light bombers.
But the .50 Gatling development started in 1982, yes?
So (as I said) the idea was overlooked.